image_caption <- function(URL) {
 reqURL = paste0(vision_api_endpoint,
                 "/analyze?visualFeatures=Description",
                 "&details=Celebrities,Landmarks")
 
 APIresponse = POST(url = reqURL,
                    content_type('application/json'),
                    add_headers(.headers = c('Ocp-Apim-Subscription-Key' = vision_api_key)),
                    body=list(url = URL),
                    encode = "json") 
 
 df = content(APIresponse)
 cat(URL, "\n")
 cat(paste0("Confidence: ",df$description$captions[[1]]$confidence,"\n"))
 cat("Wikimedia Commons description:\n", attr(URL,"desc"),  "\n")
 cat("Vision API description:\n",  df$description$captions[[1]]$text,"\n")
 invisible(df)
}